OF SELBORNE. 77 



of grass and leaves. At one end of the burrow lay above a 

 gallon of potatoes regularly stowed, on which it was to have 

 supported itself for the winter. But the difficulty with me is 

 how this amphibius mus came to fix it's winter station at such 

 a distance from the water. Was it determined in it's choice 

 of that place by the mere accident of finding the potatoes 

 which were planted there ; or is it the constant practice .of the 

 aquatic-rat to forsake the neighbourhood of the water in the 

 colder months? 



Though I delight very little in analogous reasoning, know- 

 ing how fallacious it is with respect to natural history ; yet, in 

 the following instance, I cannot help being inclined to think 

 it may conduce towards the explanation of a difficulty that I 

 have mentioned before, with respect to the invariable early 

 retreat of the hirundo opus, or swift, so many weeks before 

 its congeners ; and that not only with us, but also in Andalu- 

 sia, where they also begin to retire about the beginning of 

 August. 



The great large bat 1 (which by the by is at present a non- 

 descript in England, and what I have never been able yet to 

 procure) retires or migrates very early in the summer : it 

 also ranges very high for it's food, feeding in a different region 

 of the air ; and that is the reason I never could procure one. 

 Now this is exactly the case with the swifts ; for they take 

 their food in a more exalted region than the other species, and 

 JHV very seldom seen hawking for flies near the ground, or 

 over the surface of the water. From hence I would conclude 

 that these hirundines, and the larger bats, are supported by 

 some sorts of high-flying gnats, scarabs, or phalcence, that are 

 of short continuance ; and that the short stay of these strangers 

 is regulated by the defect of their food. 



By my journal it appears that curlews clamoured on to 

 October the thirty-first ; since which I have not seen or heard 

 any. Swallows were observed on to November the third. 



1 The little bat appears almost every month in the year ; but I have 

 lu'vi'i- seen the large ones till the end of April, nor after July. They are 

 most common in June, but never in any plenty : are a rare species with us. 



